bathroom earthing question

Ok, this is probably a very stupid question, so apologies, but..

The is no earthing in my bathroom, i.e. the radiator, hot and cold pipes to bath, basin, toilet, also the plugs and overflows. The only thing that is earthed is the 8.5kw shower.

Anyway looking on t'internet it appears that I need to cross bond all of the above items with earth wire and then connect to the earth terminal in the shower isolating pull cord switch.

Ok, here is the stupid question, currently (pardon the pun), there is no danger of me getting an electric shock, as I never do, and never will take any electrical item into the bathroom, and secondly the electric shower has been connected correctly. So if I was to carry out the earthing work as per regs, then wouldn't I be increasing the chances of an electric shock.

Basically I have a irrational fear that somehow the earth lead will someday work its way out of the terminal in the bathroom isolater switch and then make contact to the live terminal, and now suddenly all the earthed stuff is live.

I want to get the bathroom upto spec, but I genuinely feel It'll make the bathroom less safe.

See I told you it was a stupid question :-}

Jon

Reply to
jon
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Not so, electricity takes the path to earth with least resistence, IE straight down the copper pipes, hence the copper strips running up church walls to lightning conductors on the roof, in other words, I could stand on a church roof during a thunderstorm wearing nothing but a suit of armour and not get struck by lightning because I'm not earthed as well as the lighning conductor.

It's a common misconception, but stainless steel sinks have been earthed this way for decades without anyone getting fried while washing dishes, any power getting to the sink will not be felt by the person with wet hands because they offer too much resistance in comparison to a copper pipe straight into the ground.

Reply to
Phil L

Not in normal circumstances.

Which would not give you an electric shock. To get an electric shock there has to be a voltage (*potential difference*) between two points. The bonding is not there to earth the bathroom, it is there to join every conductive part entering the bathroom to form an equipotential zone. This equipotential bonding prevents the difference in potential (voltage) rising to a dangerous level.

To take an admittedly extreme and theoretical example, and I do not recommend this in practice, you should stick a 240V live cable in your mouth while standing in the bath and not feel the slightest tingle PROVIDED that the bath (and thus you) was also at 240V through the equipotential bodning.

However as your bath is not bonded your "faulty earthed" shower could be at 240V and your bath will probably have some form of earth through the plumbing, so there is a potential difference and the possibility of current flow through your body. D'you want to phone an undertaker now?

It is actually somewhat safer not to have any conductive parts entering the bathroom ie use plastic pipe in which case bonding is not required. However, as most bathrooms tend to be "earthy" having all the conductive parts bonded together and then earthed via the circuit protective conductors (earth wires in circuit cables) means that any fault to earth will cause sufficient fault current to flow to operate the MCB or RCD suitably quickly.

Owain

Reply to
Owain

But then we have the question of plastic pipes ..???...lol

Stuart

Reply to
Stuart

On Thu, 09 Mar 2006 20:49:35 GMT someone who may be "jon" wrote this:-

Far better to connect the bonding to the earth terminal in the shower.

Reply to
David Hansen

Have a look at

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well

Adam

Reply to
ARWadsworth

Cheers, the mother-in-law visits on the weekend, i'll test your theory then.

Jon

Reply to
jon

She was so ugly not even the tide would take her out...

Mungo :-) [Ni real disrespect to your mother-in-law Jon]

Reply to
Mungo

Common misconception this. That is about regs applying to new installs, there is no reason you would need to add crossbonding. The safety benefit of crossbonding is approximately zero since the level of protection against electrocution is already extremely good.

In terms of safety benefit per time and money spent, retrofitting crossbonding is a non-starter. Your stairs are 1000s of times more likely to kill you, as are various other things.

fwiw you'll normally find most of the above are already earthed. You can test with a meter if you want.

NT

Reply to
meow2222

I bet you wouldn't be willing to put your money where your mouth is..? ;-)

Mathew

Reply to
Mathew Newton

Frankly this is ridiculious. There are such things as "leakage currents" and even lightning conductors will melt if the pulse/energy duration lasts long enough. And, there is more than ONE path to earth in the real world.

The leakage current through your suit of armour may well be enough to see you off. I don't suggest you try it.

Reply to
dave

First, lightning is completely irrelevant to the OP's question. Second, leakage currents are irrelevant. That suit of armour puts the human inside a Faraday cage. Therefore a direct lightning strike that might kil the exposed human would become not harm the human inside that conductive armour.

Third, there may be many paths to earth. But when only one has significantly less impedance (not just resistance) - is electrically a much shorter path - then a lightning bolt will take only that path to earth. This is why lightning rods, properly earthed, provide a cone of protection. This is why long distance transmission lines - the most likely item to be struck - are at little risk from lightning being beneath a well earthed catenary wire.

But aga> > Frankly this is ridiculious. There are such things as "leakage currents" and

Reply to
w_tom

Solutions defined with detail in that

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.pdf document demonstrate techiques that have been standard or are slowly becoming standard most everywhere in the past 30 years. This was required in North America starting about 1970. Best way to address electric safety starts by not worrying what you do or do not use in the bathroom. That picture of a human in a bathtub using a hairdryer to blow a sailing boat is what you - the owner of a building - must address.

Start by putt>> recommend this in practice, you should stick a 240V live cable in your

Reply to
w_tom

Solutions defined with detail in that

formatting link
.pdf document demonstrate techiques that have been standard or are slowly becoming standard most everywhere in the past 30 years. This was required in North America starting about 1970. Best way to address electric safety starts by not worrying what you do or do not use in the bathroom. That picture of a human in a bathtub using a hairdryer to blow a sailing boat is what you - the owner of a building - must address.

Start by putt>> recommend this in practice, you should stick a 240V live cable in your

Reply to
w_tom

Hair driers used in baths was a US-specific problem. We had put rules in place to prevent that before WWII. Even other countries which still haven't don't have the same problem the US did with electrocutions in baths.

You are wrong on just about every count here with regards to UK regs.

Reply to
Andrew Gabriel

Run that last part past me again please ......lol

Stuart

Reply to
Stuart

Oh dear... It was meant to say...

Even other countries which still haven't [put rules in place] don't have the same problem the US did with electrocutions in baths.

Reply to
Andrew Gabriel

So why does a UK article on bathroom protection

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show a British citizen in a bathtub using a hairdryer to move a sailing ship? Clearly they are not discussing only hairdryers in the bathtub. Clearly they are discussing and I was discussing any electrical appliance, light, etc in a bathroom. An RCD that trips on low amperage ground fault currents is a very effective solution to bathroom human safety - no matter what is required by code. This because the average bathroom in any country contains electrical appliances and lamps.

Does

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discuss bathroom electrical safety everywhere but the UK? I don't think so. They use a 'hardryer in a bathtub' as an example of what even UK bathroom wiring should consider possible. Stupid? Yes. And possible in any nation that has electricity in bathrooms. An RCD for bathroom circuits has been standard in the States since 1970 because sometimes people use electrical appliances in the wrong place. If not yet required in the UK, well, RCD for bathrooms is a safety solution long overdue and strongly encouraged.

Reply to
w_tom

While what you say probably applies in the US, its wrong on nearly all points wrt to the UK.

Why does someone show a picture or make a claim? Because they have an agenda maybe?

NT

Reply to
meow2222

Well that reasoning is good and sufficient for an English major. But a technical person would your entire post. Why? Where are the list of details for why "its wrong on nearly all points wrt to the UK". Fine to have an opinion if you keep it to yourself. But when details of "why" are not provided, then it becomes a post so typical of political extremists such as Rush Limbaugh. If your post has merit, then it includes technical WHYs. Without the 'whys' - those essential technical details - it is simply what propagandists, political extremists, and liars do.

If RCDs do not provide human safety to UK bathrooms, they why? Why is electricity at 230 volts in UK bathrooms not a threat when electricity in Canada and US at 120 volts has been considered dangerous since 1970s. Why is UK electricity not dangerous in UK bathrooms - especially when RCDs are so inexpensive?

Reply to
w_tom

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